Heat Pumps...

[Snatch1]

Are they worth it?

I'm about to order an EV6 GT AWD through the company lease scheme. The heat pump is a £900 option and takes me over budget so I'll be paying for it monthly out of my own pocket.

I've read a lot about this subject and I'm leaning towards not bothering with one but thought I'd ask the PH masses for any real world experience.

95% of my journeys will be less than 100 mile round trip. I would expect to have to charge away from home less than once or twice a month so am struggling to see the need for the heat pump as a means of improving range, it'll be more to heat the cabin quickly on really cold days.

[curvature]

Not sure that I can really answer your question but being able to get into a nice warm car on a winter morning is a nice touch.

However as it is not your car I would save the money.

You can still switch the car on and heating / heated seats whilst you clear the windscreen but like all vehicles it takes fuel to do this wether it be electric or petrol.

Incidentally I looked at the EV6 but couldn't get a test drive of a GT. In the end I went for an iX3 as I just preferred the interior and the deals were far better at the the time. (Dec 23)

Edited by curvature on Friday 12th January 12:22

[sherbertdip]

I think "worth it" is very subjective, will you ever save the £900 in electricity heating with a heat pump rather than resistive element?

I have a niggling memory that the heat pump on the EV6 was for battery conditioning not cabin heating, although that was from first release, the spec may have changed and more so on the GT.

My lowly Ioniq has a heat pump as standard I do find it very effective but can be vaguely heard when sat at traffic lights and it is at full power on demist setting.

[JonnyVTEC]

curvature said:

Not sure that I can really answer your question but being able to get into a nice warm car on a winter morning is a nice touch.

However as it is not your car I would save the money.

You can still switch the car on and heating / heated seats whilst you clear the windscreen but like all vehicles it takes fuel to do this wether it be electric or petrol.

Incidentally I looked at the EV6 but couldn't get a test drive of a GT. In the end I went for an iX3 as I just preferred the interior and the deals were far better at the the time. (Dec 23)

Edited by curvature on Friday 12th January 12:22

It will preheat regardless. Please lets not make a confusion on the features.

Heat pump just means you can get 4kW of heating into the cabin with 1.5kW of HV load, the heater on none heatpumps will just mean 4kW of battery draw for 4kW of heat. Its an efficiency thing based of the CoP of moving energy rather than creating it, thats why its called a heat pump, it moves heat around.

[AlexIT]

sherbertdip said:

I think "worth it" is very subjective, will you ever save the £900 in electricity heating with a heat pump rather than resistive element?

Actually more than the cost, which you'll probably never recover, I would check how much does the resistive element impacts on the range. We're having an average of -2 in the morning to +5 in the day here and I think that on a longer journey (3 hours +) not having a heat pump could add a stop on the route.
If the car's used for shorter trips and charged mostly at night, then I wouldn't mind too much.

OTOH I have no idea how effective demisting is without a heatpump

[Snatch1]

Thanks for the replies, all good input.

I realsied I made an error in my original post, it's the EV6 GT Line AWD I'm looking at, not the GT - budget certainly doesn't stretch to the GT as much as it might be nice to have that 570hp!

Edited by Snatch1 on Friday 12th January 12:49

[samoht]

JonnyVTEC said:

It will preheat regardless. Please lets not make a confusion on the features.

Heat pump just means you can get 4kW of heating into the cabin with 1.5kW of HV load, the heater on none heatpumps will just mean 4kW of battery draw for 4kW of heat. Its an efficiency thing based of the CoP of moving energy rather than creating it, thats why its called a heat pump, it moves heat around.

+1

I would expect the actual amount of heat available to be similar with or without a heat pump, as Kia will base that on their idea of the user's requirement. It's just that the battery energy required to achieve it will be less with a heat pump.


Presumably if you're leasing the car, you would pay the £900 for the heat pump but lose that money when the car goes back, not like if you own it and it might be worth a bit more used with the option.


If you're driving well within the car's range I can't see a big issue.
At 70mph the cabin heat is proportionately less significant, because the power to drive the car is greater (25 kW?) and you cover more miles per unit time. Maybe 10-20% extra energy draw?
The difference would probably be most noticeable at lower speeds where the motor is pulling less power.


Do/will you have a home charger? Preconditioning works better if you do, the cabin heater likely draws the full 7 kW so if you have a home charger then that comes straight from the supply; a three-pin charger can only supply 2-3 kW, so even when plugged in, preconditioning will use some battery energy. Either way preconditioning while plugged in will lessen the energy needed for cabin heating.


It feels 'better' to have a heat pump as it's 'more efficient', but if it's just a lease car and if you're only going to do a handful of longer trips in cold weather each winter, I'd agree that it's hard to justify paying the extra £900.

[Road2Ruin]

There is no way the cabin heater draws 7kw. I would guess about 1kw. A normal fan heater is around 1 to 2 kw and they pump out huge amounts of heat. Our car, you can barely notice it.

[blank]

I wouldn't bother if you don't need the range boost.

Heating performance will be more than adequate with the standard resistive heating.

I have a PHEV (so tiny battery in comparison and I imagine tiny heater!) and it's absolutely fine when it's below 0 outside. Pre-heats when plugged in and maintains 20degC and mist free with everything on "auto" while driving.

[samoht]

To clarify, I meant when it's cold outside and the car starts preconditioning, e.g. to raise the temp from zero degrees to 21 degrees in the car, it'll draw around 7 kW for a period to heat the car as quickly as possible.

I don't think it uses that sort of power once the car's warmed up on an ongoing basis. I have seen someone observe a 7 kW draw on max heat:

https://www.speakev.com/threads/working-obd.168226...

Memosis said:

With everything at MAX it consumes 7kW with occasional 10kW peaks (full LED headlights, AC at highest temperature ("HI"), heated steering wheel, seats, fans, radio...)

Not an EV6, but likely an EV6 would be higher if anything.

[Knock_knock]

Over the last few mornings (-2 to -4) I have observed initial draw for heating to be about 6kW, dropping steadily until after about 15 minutes it's been just under 1kW which maintains the 21' I like.

That is with a heat pump.

Without the heat pump I expect the final draw would have been closer to 3kW.

Heat pump is definitely more efficient in that respect and will mean a bump in range over a vehicle using solely resistance heating for the same journey. Whether that is significant enough probably depends on your usage. If you'll be pushing the range to the max regularly then probably more significant than if you'll be charging every couple of days and using 40% of your battery in that interval. £900 is lot unless you really need the extra, I would suggest...

[JonnyVTEC]

Road2Ruin said:

There is no way the cabin heater draws 7kw. I would guess about 1kw. A normal fan heater is around 1 to 2 kw and they pump out huge amounts of heat. Our car, you can barely notice it.

It’s heating fluid for the full battery and cabin system, not just air. 4-5kW is typical, some also have dedicated battery heaters too.

[Scrimpton]

My little Ioniq will draw 4.5kw for climate on a really cold morning.

[dvs_dave]

JonnyVTEC said:

Road2Ruin said:

There is no way the cabin heater draws 7kw. I would guess about 1kw. A normal fan heater is around 1 to 2 kw and they pump out huge amounts of heat. Our car, you can barely notice it.

It’s heating fluid for the full battery and cabin system, not just air. 4-5kW is typical, some also have dedicated battery heaters too.

Yep. They’re typically rated at 7kW. Certainly the one in my egolf is. Doesn’t mean it’s always pulling that much, but they do initially to get things warmed up quickly, then ramp down as necessary.

It’s also worth noting that even with a heat pump, there is often a resistive heater for backup as heat pumps don’t work well when it’s very cold. Unless like Tesla it can do clever stuff like deliberately run the motors and other electronics inefficiently to generate the heat for cabin heating.

[Tophatron]

An interesting thing with EV heat pumps is that many of the cars with them also have a resistive heater too, which is used when it's very cold and/or to give an initial blast of heat before the heat pump takes over - so you'd only see the benefit over a longer drive.

Going by what you've said OP, I wouldn't bother with adding a heat pump.

[sherbertdip]

Tophatron said:

An interesting thing with EV heat pumps is that many of the cars with them also have a resistive heater too, which is used when it's very cold and/or to give an initial blast of heat before the heat pump takes over - so you'd only see the benefit over a longer drive.

Going by what you've said OP, I wouldn't bother with adding a heat pump.

I did wonder if my Ioniq was like that as the heating is pretty much there within a minute of powering up, on demist it's actually rather hot, much quicker and hotter than I would have thought the heatpump could achieve.

[Tractor Driver]

Am I right in thinking that heat pumps are also advantageous in warm weather for making air conditioning more efficient too?

[JonnyVTEC]

Tractor Driver said:

Am I right in thinking that heat pumps are also advantageous in warm weather for making air conditioning more efficient too?

AC is a single direction heatpump. Heat pumps work both ways. So in terms of cooling theres no difference.

[TheDeuce]

JonnyVTEC said:

Road2Ruin said:

There is no way the cabin heater draws 7kw. I would guess about 1kw. A normal fan heater is around 1 to 2 kw and they pump out huge amounts of heat. Our car, you can barely notice it.

It’s heating fluid for the full battery and cabin system, not just air. 4-5kW is typical, some also have dedicated battery heaters too.

I was told the same for EV heaters, climate plus battery compartment. 2-4kw is fairly typical.

But as others have said, a car is a tiny space and once it's very rapidly heated initially, keeping it up to temp will require far less power. Perhaps a couple of hundred watts/hr. Also factor in that EV's tend to have a higher level of insulation to keep road noise out as its not disguised by ICE background noise, it's sound insulation but it will have thermal benefits too.

For the period of ownership it seems unlikely that the £900 cost would ever be re-couped. It will also extend the cars range on colder days... but likely not by enough to justify the cost.

[Evanivitch]

Road2Ruin said:

There is no way the cabin heater draws 7kw. I would guess about 1kw. A normal fan heater is around 1 to 2 kw and they pump out huge amounts of heat. Our car, you can barely notice it.

Ampera would draw 6kW heating cabin.